This invention relates to the fabrication of continuous envelopes, and more particularly to a method and apparatus for manufacturing envelopes which are adapted for use with electronic data processing printers or the like.
The demand for continuous envelopes is based in large measure on the ease by which standardized correspondence is simultaneously distributed to a large number of distinct individuals in an economic manner. The user need only maintain a computerized master listing which in turn is used with electronic printers to economically and rapidly generate pre-addresed envelopes or mailers for distribution. The problem is, however, that the recipient is generally well aware that the piece of correspondence has in fact been distributed to many others since the construction of the envelope itself will indicate this fact. Indeed, many charitable solicitations or other correspondence may even be discarded unopened because the recipient does not want to be bothered with so-called "junk mail," when the enclosures would otherwise merit their interest and attention.
The extensive efforts to emulate the appearance of the conventional folded envelope, while obtaining the advantages of computerized addressing, are reflected widely in the art. A representative prior continuous envelope construction is depicted in U.S. Pat. No. 3,026,018. As can be seen by reference to the drawings in that patent, envelopes which are fabricated from a continuous paper web in accordance with known methods have characteristic small triangular cut-outs on the backing panels to form a generally rectangular closure flap and in turn an overall rectangular appearance for the envelopes, as distinguished from the tapered appearance of the closure flap to an apex on an envelope manufactured by conventional means, i.e. by folding a pre-cut, discrete form or blank. As disclosed in the above patent, a die cutting operation may be employed to form the small triangular cut-outs. However, a die cutting operation has not been found to be suitable for forming larger cut-outs of elongate triangular outline which would permit the closure flap to more closely approximate the appearance of the flap of a conventional envelope, since the larger die blades are expensive, and they are not able to uniformly sever cut-outs of elongate, relatively narrow triangular outline.
Since commercial manufacturers of continuous envelopes have lacked a satisfactory method for forming generally acceptable envelopes from a continuous paper web, they have turned to forming discrete and essentially conventional envelopes from blanks which are thereafter mounted on a distinct carrier sheet or alternatively glued together in series so that they may be advanced through an electronic printer. While the resultant product does resemble a conventional envelope for readily apparent reasons, these methods are very costly and inefficient. In this regard, U.S. Pat. Nos. 2,824,686; 3,219,258; 3,547,343 and 3,565,728 are representative. A still further effort in this field is represented by U.S. Pat. Nos. 2,790,593 and 4,102,251. In accordance with the methods described in these patents, discretely formed envelope backing panels or "ply segments" are adhered to a continuous web of "patch portions." The problems with this approach which are set forth in part in the latter reference, reside in accurately indexing the discrete ply segments onto the continuous web of envelope patches. Moreover, the resulting envelope product noticeably bears the dubious and telltale indicia of the conventional continuous envelope with all of the attendant disadvantages as described above.
In addition to providing a continuous envelope product having a suitable backing panel construction, it is also desirable to provide an envelope patch for application to the backing panels which includes an insert slot for facilitating the insertion of the correspondence or mailer by conventional automated equipment. As in the case of the envelope backing panels, it would be particularly desirable to manufacture these patches from a continuous paper web both from the standpoint of economy and precision. To date, however, no satisfactory method or apparatus to accomplish these objectives has been achieved. Instead, the prevailing methods in use utilize a totally rectangular patch (with no slot) which is discretely formed and then applied by gripper means, which lift a single, discrete patch, and then deposit it on an envelope backing panel as the stream of previously formed envelope backing panels is advanced. This procedure leads to significant indexing problems and creates a significant limitation on the overall speed of the envelope fabrication process.
It is therefore an object of the present invention to provide a method and apparatus for efficiently manufacturing continuous envelopes which are adapted for use with electronic data processing printers or the like, and which overcome the disadvantages and limitations of the prior practices.
It is a more particular object of the present invention to provide a method and apparatus for fabricating continuous envelopes, and which is adapted to provide for the effective formation of relatively large, elongate rectangular cut-outs in an advancing web of paper and so that the flap portions of the resulting envelopes may have the appearance of the flap portions of conventional envelopes.
It is also an object of the present invention to provide a method and apparatus for forming generally rectangular envelope patch portions, preferably having an insert slot, which are also formed from a continuous paper web and which may be accurately advanced and adhered to a continuous web of the backing panels, and so that the resulting envelopes further resemble conventional envelopes in appearance as well as function.
It is another object of the present invention to provide a method and apparatus which accomplishes the foregoing objects at relatively high operating speeds without compromising the high quality of the products.